Drug Summary

Nitroglycerin (Nitrostat®)

Pharmacologic properties:

Nitroglycerin is an organic nitrate which causes systemic vasodilation by entering vascular smooth muscle, converting to nitric oxide, and activating cGMP. This dose-dependent dilation acts primarily on the venous system, although it also produces direct coronary artery vasodilation as well. The overall result is a decrease in venous return which decreases the workload on the heart and thus, decreases myocardial oxygen demand. Nitroglycerin also improves blood flow to the myocardium and lowers systemic blood pressure.

Indications:

  • Chest pain with suspected cardiac ischemia
  • Suspected acute myocardial infarct
  • Acute dyspnea with suspected pulmonary edema/congestive heart failure

Contraindications:

  • Hypertension associated with acute stroke or severe brain injury
  • Systolic BP < 90 mmHg
  • Phosphodiesterase-5 inhibitor use within 24 hours (Viagra® or Levitra®) or 48 hours (Cialis®)

Precautions:

  • Use with caution in acute inferior wall MI or right ventricular infarct (ST elevation in V4R) - be prepared to administer 250 mL NS bolus if hypotension develops
  • Patients on chronic nitrate therapy may require larger doses of nitroglycerine during acute anginal episodes
  • Nitro tablets are inactivated by light, air and moisture and must be kept in amber glass containers with tight-fitting lids
  • Alcohol will accentuate vasodilating and hypotensive effects

Adverse Reactions:

  • Headache
  • Hypotension
  • Tachycardia
  • Dizziness
  • Flushing
  • Nausea and vomiting

Dosage and administration:

  • 0.4 mg spray or tablet sublingually, every 5 minutes as needed if no contraindication develops